Chemistry

Chemical Reactions and Processes

571 Questions

Chemical reactions and processes questions cover the transformation of substances through electrolysis, thermal decomposition, and catalysis. Key areas include identifying gas evolution, balancing chemical equations, and understanding industrial chemical applications. This general chemistry topic is a staple in the science sections of multiple competitive examinations.

Thermal decompositionElectrolysis processGas evolution reactionsHeterogeneous catalystsFuel cell components

Chemical Reactions and Processes Questions

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

Assertion (A): In the synthesis of ammonia by Haber's process, mixture of potassium and aluminium oxides can be used as promoter.
Reason (R): Promoter enhances the activity of catalyst.

  1. Both (A) and (R) are true and (R) is the correct explanation of (A)

  2. Both (A) and (R) are true and (R) is not the correct explanation of (A)

  3. (A) is true and (R) is false

  4. (A) is false but (R) is true
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Promoter enhances the activity of catalyst (here iron), and because of which potassium and aluminium oxides are used as promoter in Haber's process.

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

In Haber process of  Ammonia production the element used as catalytic promoter to increase the activity of Iron catalyst is .......................

  1. NI (Nickel)

  2. W (Tungston)

  3. V (Vanadium)

  4. Mo (Molybednum)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In Haber process of  ammonia production the element used as catalytic promoter to increase the activity of Iron catalyst is Mo (Molybednum).
$N _2+3H _2  \rightleftharpoons 2NH _3 + 24 \quad kcal$
The temperature is $450^oC$ and  the pressure is 200-250 atm.

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia
Nitrogen reacts with a metal $M$ to produce a compound $X$. This compound $X$ when dissolved in water forms pungent gas $Y$ which can be identified easily by the formation of white fumes in the presence of $HCl$.

Identify Y:

  1. Nitrogen dioxide

  2. Ammonia

  3. Nitrous oxide

  4. Nitric oxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
$ 3Ca+{ N } _{ 2 }\xrightarrow [ \Delta  ]{  } { Ca } _{ 3 }{ N } _{ 2 } $

$ { Ca } _{ 3 }{ N } _{ 2 }+6{ H } _{ 2 }O\xrightarrow [  ]{  } 3Ca{ (OH) } _{ 2 }+2N{ H } _{ 3 } $
From the reaction we can see that the metal $ M $ is $Ca$ and pungent gas $ Y $ is Ammonia. 
Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

A solution of colorless salt H on boiling with excess NaOH produces a non-flammable gas. The gas evolution ceases after sometime upon addition of Zn dust to the same solution, the gas evolution restarts. The colourless salt(s) H is(are) :

  1. $NH _4NO _3$
  2. $NH _4NO _2$
  3. $NH _4Cl$
  4. $(NH _4) _2SO _4$
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation
Option (A), (B) are correct.
The colorless salt H is either $NH _4NO _3$ or $NH _4NO _2$. The colorless salt produces $NH _3$ gas (non-inflammable) on boiling with excess of $NaOH$. On addition of zinc dust (a reducing agent) to this solution, sodium nitrite or sodium nitrate will liberate $NH _3$ gas again.
 
$NH _4NO _3+ NaOH \longrightarrow NH _3+NaNO _3+H _2O$
$7NaOH+NaNO _3+4Zn\longrightarrow 4Na _2ZnO _2+NH _3+2H _2O$

$NH _4NO _2+NaOH \longrightarrow NaNO _2+NH _3+H _2O$
$3Zn+5NaOH+NaNO _2 \longrightarrow 3Na _2ZnO _2+NH _3$
Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

Which of the following when dissolved in water will liberate ammonia ?

  1. ${Na NO _3}$
  2. ${Na NO _2}$
  3. ${Na NH _2}$
  4. ${Na _3N}$
Reveal answer Fill a bubble to check yourself
C,D Correct answer
Explanation

Reactions:
$Na _3N+ 3H _2O \rightarrow 3NaOH + NH _3$
$H _2O+NaNO _3\rightarrow H _2O+NaOH+NO$
$NaNH _2+H _2O(hot) \rightarrow NaOH + NH _3$
$NaNO _2 + H _2O \rightarrow HNO _2 + NaOH$

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

Magnesium on heating to redness in an atmosphere of $N _{2}$ and then on treating with $H _{2}O$ gives?

  1. $NH _{3}$
  2. $H _{2}$
  3. $N _{2}$
  4. $O _{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Megnesium when heated with $N _2$ in atmosphere it forms magnesium nitride($Mg _3N _2$) which on hydrolysis(reaction with water) gives ammonia.
$3Mg+N _2\rightarrow Mg _3N _2$
$Mg _3N _2+6H _2O\rightarrow 3Mg(OH) _2+2NH _3$.
Hence option A is correct.
Multiple choice bio-chemistry proteins denaturation of protein proteins and amino acids proteins and enzymes

What type of a chemical reaction takes place when,
(i) lime stone is heated?
(ii) proteins are converted into amino acids?

  1. In both (i) and (ii), a combination reaction takes place

  2. In (i), a decomposition reaction takes place while in (ii), a combination reaction takes place

  3. In both (i) and (ii), a decomposition reaction takes place

  4. In (i), a combination reaction takes place while in (ii), a decomposition reaction takes place
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lime stone is calcium carbonate which, upon heating, decomposes into calcium oxide and carbon dioxide.

$CaCO _3 \rightarrow CaO + CO _2$
 Similarly, proteins also undergo decomposition to form amino acids.
$ (-Amino \ acid-) _n \rightarrow n Amino \ acids$

Multiple choice

What is the primary mechanism responsible for the gas sensing properties of certain ceramic functional materials?

  1. Chemisorption

  2. Physisorption

  3. Redox reactions

  4. Structural changes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In ceramic gas sensors, the gas sensing properties often arise from chemisorption, where gas molecules react with the surface of the ceramic material, leading to changes in electrical or optical properties.

Multiple choice

What is the chemical reaction that takes place during the discharge of a lead-acid battery?

  1. Pb + PbO2 + 2H2SO4 → 2PbSO4 + 2H2O

  2. Li + LiCoO2 → LiCoO2 + e-

  3. Ni(OH)2 + Cd(OH)2 → NiOOH + Cd + H2O

  4. Zn + CuSO4 → ZnSO4 + Cu
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During the discharge of a lead-acid battery, the following chemical reaction occurs: Pb + PbO2 + 2H2SO4 → 2PbSO4 + 2H2O. This reaction results in the conversion of lead and lead dioxide to lead sulfate, while sulfuric acid is consumed.

Multiple choice

What is the name of the process by which hydrogen is produced from biomass?

  1. Steam reforming

  2. Electrolysis

  3. Gasification

  4. Fracking
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Gasification is the process by which hydrogen is produced from biomass.

Multiple choice

How is hydrogen produced?

  1. Electrolysis of water

  2. Steam reforming of natural gas

  3. Coal gasification

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Hydrogen can be produced through various methods, including electrolysis of water, steam reforming of natural gas, coal gasification, and other processes.

Multiple choice

What is the process of splitting water into hydrogen and oxygen called?

  1. Electrolysis

  2. Hydrolysis

  3. Pyrolysis

  4. Combustion
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Electrolysis is the process of splitting water into hydrogen and oxygen using an electric current.

Multiple choice

Which type of surface reaction is dominant on dust grains in the interstellar medium?

  1. Acid-base reactions

  2. Redox reactions

  3. Radical-radical reactions

  4. Nucleophilic substitution reactions
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Radical-radical reactions, involving the combination or disproportionation of free radicals, are the dominant type of surface reaction on dust grains in the interstellar medium.